Signal decoding methods, apparatus and systems

ABSTRACT

The present invention relate generally to signal encoding and decoding. One claim recites a method comprising: obtaining color image data or color video data, the color image data or color video data comprising an encoded signal pattern, the encoded signal pattern aiding detection of an encoded message, the pattern comprising first frequency components and second frequency components, the color image data or color video data comprising first color data and second color data, in which the first color data comprises the first frequency components encoded therein, and the second color data comprises the second frequency components encoded therein; combining the first color data and the second color data, said combining yielding combined color data; utilizing one or more processors or electronic processing circuitry, detecting the encoded signal pattern from the combined color data, said detecting yielding rotation and scale information; and using the rotation and scale information to detect the encoded message from the combined color data. Of course, other combinations and claims are provided too.

RELATED APPLICATION DATA

This application is a continuation of U.S. application Ser. No.15/131,961, filed Apr. 18, 2016 (now U.S. Pat. No. 9,665,919) which is acontinuation of U.S. application Ser. No. 14/572,478, filed Dec. 16,2014 (now U.S. Pat. No. 9,317,888) which is a continuation of U.S.patent application Ser. No. 13/963,627, filed Aug. 9, 2013 (now U.S.Pat. No. 8,913,780) which is a continuation of U.S. patent applicationSer. No. 12/636,561, filed Dec. 11, 2009 (now U.S. Pat. No. 8,509,474)which claims the benefit of U.S. Provisional Patent Application No.61/140,540, filed Dec. 23, 2008. The 61/140,540 application is herebyincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to steganographic data hidingand digital watermarking.

BACKGROUND AND SUMMARY

The term “steganography” generally means data hiding. One form of datahiding is digital watermarking (or simply “watermarking” as used in thisdocument). Digital watermarking is a process for modifying media contentto embed a machine-readable (or machine-detectable) signal or code intothe media content. For the purposes of this document, the data may bemodified such that the embedded code or signal is imperceptible ornearly imperceptible to a user, yet may be detected through an automateddetection process. Unlike overt symbologies (e.g., barcodes), an unaidedhuman eye or ear generally will not be able to discern the presence ofthe digital watermark in imagery (including video) or audio. Mostcommonly, digital watermarking is applied to media content such asimages, audio signals, and video signals.

Digital watermarking systems may include two primary components: anembedding component that embeds a watermark in media content, and areading component that detects and reads an embedded watermark. Theembedding component (or “embedder” or “encoder”) may embed a watermarkby transforming (or altering or modifying) data samples representing themedia content in the spatial, temporal or some other domain (e.g.,Fourier, Discrete Cosine or Wavelet transform domains). The readingcomponent (or “reader” or “decoder”) analyzes target content to detectwhether a watermark is present. In applications where the watermarkencodes information (e.g., a message or payload), the reader may extractthis information from a detected watermark.

A watermark embedding process may convert a message, signal or payloadinto a watermark signal. The embedding process then combines thewatermark signal with host media content and possibly other signals(e.g., an orientation pattern or synchronization signal) to createwatermarked media content. The process of combining the watermark signalwith the media content may be a linear or non-linear function. Thewatermark signal may be applied by modulating or altering signal samplesin a spatial, temporal or some other transform domain.

The above mentioned orientation pattern is helpful in identifying thewatermark signal during detection. It can also provide helpfulorientation clues regarding rotation, scale and translation (e.g.,distance from origin) of the watermark signal.

A watermark encoder may analyze and selectively transform media contentto give it attributes that correspond to the desired message symbol orsymbols to be encoded. There are many signal attributes that may encodea message symbol, such as a positive or negative polarity of signalsamples or a set of samples, a given parity (odd or even), a givendifference value or polarity of the difference between signal samples(e.g., a difference between selected spatial intensity values ortransform coefficients), a given distance value between watermarks, agiven phase or phase offset between different watermark components, amodulation of the phase of the host signal, a modulation of frequencycoefficients of the host signal, a given frequency pattern, a givenquantizer (e.g., in Quantization Index Modulation), etc.

The present assignee's work in steganography, data hiding and digitalwatermarking is reflected, e.g., in U.S. Pat. Nos. 6,947,571; 6,912,295;6,891,959. 6,763,123; 6,718,046; 6,614,914; 6,590,996; 6,408,082;6,122,403 and 5,862,260, and in published specifications WO 9953428 andWO 0007356 (corresponding to U.S. Pat. Nos. 6,449,377 and 6,345,104).Each of these above patent documents is hereby incorporated by referenceherein in its entirety. Of course, a great many other approaches arefamiliar to those skilled in the art. The artisan is presumed to befamiliar with a full range of literature concerning steganography, datahiding and digital watermarking.

One combination described in this disclosure is a method including:obtaining a first color channel and a second color channel, the firstcolor channel and the second color channel are components of a colorimage signal or color video signal; obtaining a digital watermarkorientation pattern, the orientation pattern serving to facilitatedetection of a watermark message; separating the digital watermarkorientation pattern into first frequency components and second frequencycomponents; utilizing a processor or electronic processing circuitry,transforming the first color channel by steganographically embedding thefirst frequency components therein; and utilizing a processor orelectronic processing circuitry, transforming the second color channelby steganographically embedding the second frequency components therein.

Another combination described in this disclosure is a method including:obtaining a first color channel, a second color channel and a luminancechannel, the first color channel, the second color channel and theluminance channel are each components of a color image signal or colorvideo signal; obtaining a digital watermark orientation pattern, theorientation pattern serving to facilitate detection of a watermarkmessage; separating the digital watermark orientation pattern into firstfrequency components, second frequency components and third frequencycomponents; utilizing a processor or electronic processing circuitry,transforming the first color channel by steganographically embedding thefirst frequency components therein; utilizing a processor or electronicprocessing circuitry, transforming the second color channel bysteganographically embedding the second frequency components therein;and utilizing a processor or electronic processing circuitry,transforming the luminance channel by steganographically embedding thethird frequency components therein.

Still another combination described in this disclosure is an apparatusincluding: a processor; and instructions for execution by the processor.The instructions include instructions to: i) obtain a first colorchannel and a second color channel, the first color channel and thesecond color channel are components of a color image signal or colorvideo signal; ii) obtain a digital watermark orientation pattern, theorientation pattern serving to facilitate detection of a watermarkmessage; iii) separate the digital watermark orientation pattern intofirst frequency components and second frequency components; iv)transform the first color channel by steganographically embedding thefirst frequency components therein; and v) transform the second colorchannel by steganographically embedding the second frequency componentstherein.

Yet another combination described in this disclosure is an apparatusincluding: a processor; and instructions for execution by the processor.The instructions include instructions to: i) obtain a first colorchannel, a second color channel and a luminance channel, the first colorchannel, the second color channel and the luminance channel are eachcomponents of a color image signal or color video signal; ii) obtain adigital watermark orientation pattern, the orientation pattern servingto facilitate detection of a watermark message; iii) separate thedigital watermark orientation pattern into first frequency components,second frequency components and third frequency components; iv)transform the first color channel by steganographically embedding thefirst frequency components therein; v) transform the second colorchannel by steganographically embedding the second frequency componentstherein; and iv) transform the luminance channel by steganographicallyembedding the third frequency components therein.

In some other combinations described in this disclosure, a watermarkmessage signal (e.g., a payload carry component) may be inserted intoone or more color channels along with isolated frequency components ofan orientation signal for that channel.

Further combinations, aspects, features and advantages will become evenmore apparent with reference to the following detailed description andaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates impulse functions as points in a spatial frequencydomain.

FIG. 2 illustrates an orientation pattern in a spatial domain.

FIG. 3 is a diagram illustrating separation of a watermark orientationsignal into different frequencies, and embedding of the differentfrequencies into different color channels.

FIG. 4 is a diagram illustrating separation of a watermark orientationsignal into different frequencies, and embedding of the differentfrequencies into different color and luminance channels.

FIG. 5 is a diagram illustrating separation of a combined watermarkorientation and message signal into different frequencies, and embeddingof the different frequencies into different color and luminancechannels.

FIG. 6a is a flow diagram of a watermark embedding process.

FIG. 6b is a flow diagram of a watermark detection process.

FIG. 7 is a graph showing a first high frequency signal.

FIG. 8 is a graph showing a second high frequency signal.

FIG. 9 is a graph showing low frequency interference from the sum of thesignals shown in FIG. 7 and FIG. 8.

FIG. 10 is a frequency plot showing a separation of frequencies.

FIG. 11 illustrates a Human Visual System (HVS) response for a printedimage.

FIG. 12 illustrates spatial frequency components separated between twocolor channels.

FIG. 13 illustrates spatial frequency components separated between threecolor/luminance channels.

DETAILED DESCRIPTION

We continue to improve the invisibility and robustness of our digitalwatermarking. The following discussion details some recent improvements.

The above mentioned orientation pattern (or orientation “component” or“signal”) may include or be represented by, e.g., a pattern of symmetricimpulse functions in the spatial frequency domain. In the spatialdomain, these impulse functions may look like, e.g., cosine waves. Oneexample of the orientation pattern is depicted in FIGS. 1 and 2. FIG. 1shows the impulse functions as points in the spatial frequency domain,while FIG. 2 shows the orientation pattern in the spatial domain. Beforeadding an orientation pattern component to a message or image (orvideo), the embedder may transform the watermark components to a commondomain. For example, if the message component is in a spatial domain andthe orientation component is in a frequency domain, the embedder maytransform the orientation component to a common spatial domain beforecombining them together. Or, the message may be transformed into atransform domain to be combined with an orientation component there.

One improvement separates digital watermark components into differentcolor channels to reduce the collective visibility of the components.This is achieved, at least in part, to reduce perceptibility of thewatermark components by adapting them to (or utilizing) the Human VisualSystem and to improve robustness by assigning more robust (and,therefore, more visible) components to color channels that are morelikely to be affected by transmission (e.g., compression).

For example, the orientation pattern discussed above can be separatedinto different frequency components, e.g., high, mid and low frequencycomponents. Separating an orientation pattern into different frequencycomponents and decomposing host media content (e.g., image or video)into different channels is performed, e.g., to take advantage of thefact that the Human Visual System (sometimes referred to as “HVS”)responses differently to information in these different frequencies andchannels.

One implementation is described with reference to FIG. 3. An orientationpattern is separated (e.g., split, divided, decomposed, and/orpartitioned, etc.) into high and low frequency components, and theseseparated frequency components are isolated to or embedded inindependent color channels. In the case of images and video, lowfrequency components are typically more visually perceptible to the HVS;whereas high frequency components are relatively less visuallyperceptible to the HVS. A simple division of the orientation patterncould be a half-way frequency (or other predetermined frequency) betweenDC and the highest possible frequency component. Alternatively, thedivision could be based on characteristics of the orientation patternitself or on characteristics of the host media signal. Yet anotheroption for separating the frequency components can be obtained throughtesting designs to identify those frequency components that are morevisible than those that are less visible. Robustness considerations canalso influence the choice of the frequency component decomposition, inaddition to HVS considerations.

Images and video can be separated into (or represented by) differentcolor channels (also called color “planes” or “directions”). Forexample, an image or video can be represented by a Blue-Yellow colorchannel, a Red-Green color channel and a luminance channel. ContrastSensitivity Function (sometime referred herein as “CSF”) curves forthese three channels show that the human eye is most sensitive tochanges in the luminance channel. Comparatively, it is less sensitive tochanges in the color channels. Among the color channels, the human eyeis less sensitive to the Blue-Yellow channel (or direction) relative tothe orthogonal Red-Green channel (or direction). CSF considers acombination of both the human eye and how the brain interprets what thehuman eye sees.

In view of how the human eye perceives the above different color andluminance channels, we designate the low frequency components (morevisible to the human eye) of the orientation pattern for embedding inthe Blue-Yellow channel (where the human eye is relatively lesssensitive). And the high frequency components (less visible to the humaneye) of the orientation pattern are designated for embedding in theRed-Green channel (where the human eye is relatively more sensitive).This frequency component-to-color channel mapping provides improvedimperceptibility for an embedded watermark.

A benefit of this frequency component-to-color channel mapping isimproved robustness. Components of the media signal that are lessvisible are usually subject to more aggressive quantization (i.e., morecompression) by compression techniques. Consequently, the Blue-Yellowchannel is likely to be more highly compressed. On the other hand, lowerfrequency components of a signal are better suited to survivecompression. Embedding the lower frequency components into theBlue-Yellow channels ensures that these frequency components survivecompression better. This provides improved robustness during detection.As a result, designating the decomposed orientation signal componentsfor embedding into the most appropriate media signal channels achievesthe desired effect of both reducing visibility of the orientation signaland increasing its robustness.

Relative to an orientation pattern, the watermark signal may have lowervisibility attributes. This is certainly the case, e.g., if thewatermark signal is a spread spectrum pattern in the spatial domain.Relatively lower visibility attributes of the watermark signal may alsobe present if the watermark signal includes a frequency domain pattern(or a modulation of frequency domain components). In this case, thefrequency decomposition (or separating) techniques discussed herein forthe orientation signal would also be applicable to the watermark signal.

A watermark signal (e.g., including a message or payload) can beembedded in a luminance channel of the image or video, and may even beembedded with a gain or signal strength greater (e.g., 2×-6× more) thanthe embedding gain or signal strength used to embed the components ofthe orientation component without significantly impacting theimperceptibility of the overall watermarking.

The Blue-Yellow channel (including low frequency components of theorientation pattern embedded therein), the Red-Green channel (includinghigh frequency components of the orientation pattern embedded therein)and the luminance channel (including the watermark signal embeddedtherein) are combined to provide a watermarked image (or video) I_(w).

FIG. 4 illustrates a related embedding method. A watermark orientationpattern is separated (e.g., split, divided, decomposed, and/orpartitioned, etc.) into high, mid and low frequency components. In thecase of images and video, low frequency components are typically morevisually perceptible to the human eye; whereas mid and high frequencycomponents are relatively less visually perceptible to the human eye.This division between frequencies can be selected either by dividing theavailable frequency domain into, e.g., thirds (or other predeterminedvalues), or by dividing the available frequency domain according tocharacteristics of the signals themselves, or through testing fordesired visibility.

The low frequency components (more visible to the human visual system)of the orientation pattern are embedded in the Blue-Yellow channel(where the human visual system is the least sensitive). The midfrequency components (relatively less visibility to the human visualsystem) of the orientation pattern are embedding in the Red-Greenchannel (where the human eye is relatively more sensitive). And the highfrequency components (even less visibility to the human visual system)are embedded in luminance channel (where the human visual system is themost sensitive). This frequency component-to-color channel mappingprovides both improved imperceptibility and improved robustness for anembedded watermark.

A watermark signal (e.g., including a message or payload) is alsoembedded in the luminance channel of the image or video. Depending onthe nature and characteristics of the watermark signal, it could also bedecomposed into separate frequency components and embedded in differentchannels of the media signal. The frequency component decomposition ofthe watermark signal could be different than that of the orientationsignal (e.g., the orientation signal may be decomposed into threecomponents, whereas the watermark signal could be decomposed into twocomponents). In this case, the components are appropriately designatedfor embedding into corresponding media content channels based oncharacteristics of the human visual system and robustnessconsiderations. And such a frequency/messagecomponent-to-color/luminance channel mapping provides improvedimperceptibility for an embedded watermark.

FIG. 5 illustrates yet another related embedding method. A watermarksignal and a watermark orientation pattern are combined to yield acomposite watermark signal. The composite watermark signal is thenseparated (or split, divided, partitioned, etc.) into high, mid and lowfrequency components. In the case of images and video, low frequencycomponents are typically more visually perceptible to the human eye;whereas mid and high frequency components are relatively less visuallyperceptible to the human eye.

The low frequency components (more visible to the human visual system)of the orientation pattern are embedded in the Blue-Yellow channel(where the human eye is relatively less sensitive). The mid frequencycomponents (which are relatively less visible to the human visualsystem) of the orientation pattern are embedded in the Red-Green channel(where the human visual system is relatively more sensitive). And thehigh frequency components (even less visible to the human visual system)are embedded in luminance channel. This frequency component-to-colorchannel mapping provides improved imperceptibility for an embeddedwatermark.

FIG. 6a is a flow diagram of one example embedding method (or operationof a watermark embedder). An image or video and a watermark signal(e.g., including an orientation pattern and message, separate orcombined) are obtained. The orientation pattern is separated intofrequency components (e.g., high, mid and low frequencies). Separatefrequency components are embedded into different color channels. Forexample, high frequency components can be embedded in a Red-Greenchannel, and low frequency components can be embedded in a Blue-Yellowchannel.

A watermark detector (or an image or video processor cooperating withthe watermark detector) reassembles the various color/luminancecomponents prior to watermark detection. For example, the color channelscan be combined or added together prior to watermark detection. Iffrequency components are embedded in a luminance channel, the followingequation can be used to reassemble the various components (e.g., for 8bit image data in this example):

Luminance=0.29*R+0.58*G+0.13*B

redGreen=0.6*R−0.3*G+128

blueYellow=−0.1*R−0.1*G+0.8*B+128

For performance reasons, the above three (3) channels above can besummed as shown below to create a single 8 bit grayscale image forpassing to a luminance-based watermark detector.

combinedLab=0.88*R+0.27*G+0.93*B−256

FIG. 6b is a flow diagram of one example of a detection method (oroperation of a watermark detector). A watermarked image or video isobtained, e.g., and first and second color channels are obtained andcombined. The image or video has been previously embedded according toat least one of the above embedding processes, e.g., with separatewatermark frequencies embedded in different color channels. A watermarkorientation pattern is detected from data representing the combinedcolor channels. For example, the data may be a transform domainrepresentation of the combined color channels. Once detected, theorientation pattern is utilized to detect a watermark message, ifpresent. For example, scale and rotation clues can be determined fromthe orientation pattern and used to find the message, or to realign thecombined color channels prior to message detection and decoding.

Returning to the discussion of watermark orientation components, wemodel or represent one example of an orientation component with thefollowing figures and equations. Of course, this discussion is notintended to be limiting, as other orientation component models orrepresentations are available. Rather, the following discussion isprovided to demonstrate some of our inventive methods, apparatus andsystems including separating watermark components into differentchannels to reduce their collective perceptibility.

With Reference to FIGS. 7 and 8, two (2) high frequency signals areillustrated, respectively I₁(x) and I₂(x), which varies with a sinuslaw:

I ₁(x)=I ₀·sin(2π·k ₁ ·x)

I ₂(x)=I ₀·sin(2π·k ₂ ·x)

Io is the sine wave magnitude; k₁ and k₂ are the respective frequenciesof the signals. The signal steps are respectively p₁=1/k₁ and p₂=1/k₂.

When I₁(x) and I₂(x) are superimposed, the resulting intensity (e.g.,producing an interference) is shown in FIG. 9 and represented by:

I(x)=I ₀·(sin(2π·k ₁ ·x)+sin(2π·k ₂ ·x));

with the Euler's formula:

${I(x)} = {{I_{0} \cdot 2}{{\cos \left( {2\pi {\frac{\left( {k_{1} - k_{2}} \right)}{2} \cdot x}} \right)} \cdot {\sin \left( {2\pi {\frac{\left( {k_{1} + k_{2}} \right)}{2} \cdot x}} \right)}}}$

With reference to FIG. 9, the resulting intensity is made of a sinus lawwith a high spatial frequency (e.g., wave number) which includes anaverage of the spatial frequencies of the two patterns, and of a sinuslaw with a low spatial frequency which is the half of the differencebetween the spatial frequencies of the two patterns. This secondcomponent is an “envelope” for the first sinus law. The wavelength λ ofthis component is the inverse of the spatial frequency

$\frac{1}{\lambda} = {\frac{k_{1} - k_{2}}{2} = {\frac{1}{2} \cdot \left( {\frac{1}{p_{1}} - \frac{1}{p_{2}}} \right)}}$

if we consider that's p₁=p and p₂=p+δp:

$\lambda = {{2\frac{p_{1}p_{2}}{p_{2} - p_{1}}} \approx {2{\frac{p^{2}}{\delta \; p}.}}}$

The distance between the zeros of this envelope is λ/2, and the maximaof amplitude are also spaced by λ/2; we thus obtain the same results asthe geometrical approach, with a discrepancy of p/2 which is theuncertainty linked to the reference that is considered: I₁(x) or I₂(x).This discrepancy is negligible when δp<<p.

Returning to FIG. 9, there is a recurring low frequency “beat” patternthat may cause objectionable visibility or perceptibility, e.g., whenembedded in a media content. The visibility of the beat patterns can beminimized by spreading the constituent frequencies apart, resulting in ahigher frequency beat pattern. (Recall from the discussion above, thathigh frequency patterns are less visible or perceptible, whereas lowfrequency patterns are more perceptible.)

One way to spread constituent frequencies may include separatingorientation component frequencies between the blue/yellow channel andred/green channels. With reference to FIG. 10, four (4) spatialfrequencies are shown (in 1-dimension). Adjacent frequencies areembedded in separate color channels. For example, the “dashed” linerepresented frequencies are embedded in a red/green channel, while thesolid line represented frequencies are embedded in the blue/yellowchannel.

Another way to spread the frequencies is to place some frequencies inthe luminance direction, and other frequencies in different colordirections.

The complete orientation pattern is reconstructed at detection by addingor otherwise combining the two color channels before passing to thewatermark detector.

To help even better understand characteristics of the HVS, FIG. 11illustrates a HVS response for a printed image held at a distance ofapproximately 12″ from the eye. Contrast Sensitivity is the HVS responseto change in contrast of luminance, Red-Green and/or Blue-Yellow.

Now let's apply this to digital watermarking to see how the HVS and theabove described methods, systems and apparatus interact. By way ofexample, please consider a digital watermark that includes the followingcharacteristics:

-   -   1. A message signal including a signal that may be approximated        with white noise up to about 75 cycles per inch; and    -   2. An orientation component including spikes in magnitude in a        frequency space, e.g., in the 10-70 cycle/inch range (e.g.,        mid-frequency band).

In one dimension, a spike (or magnitude) at say 20 cycles/inch,corresponds to a cosine wave of this spatial frequency (see FIG. 12). Noconsider two spikes (or magnitudes) at say, e.g., 30 and 50 cycles perinch on the Red-Green or Blue-Yellow CSF. The eye is relativelyinsensitive to both these spatial frequencies individually. Sensitivityof about 2 or less compared to the peak sensitivity of about 40. The lowfrequency beat produced between these two spikes (or magnitudes) is:

beatFreq=(50−30)/2=10 cycles/inch.

By looking at FIG. 11, it can be seen that the beat frequency results ina sensitivity of about 40.

By interleaving the spikes (magnitudes) between Red-Green andBlue-Yellow the beat frequency in any one color channel can be doubled.Now consider two spikes (or magnitudes), at say 10 and 50 cycles/inchfor Blue-Yellow (see FIG. 12). The low frequency beat produced betweenthese two spikes is:

beatFreq=(50=10)/2=20 cycles/inch.

With reference to FIG. 11, it can be seen that the beat frequencyresults in a sensitivity of about 15 (compared to 40 for the lowerspacing).

This could be reduced even further, be interleaving between three (3)channels, luminance, Red-Green and Blue-Yellow as shown in FIG. 13.

Now consider two (2) spikes (or magnitudes), at say 10 and 70cycles/inch for Blue-Yellow (see FIG. 12). The low frequency beatproduced between these two spikes (or magnitudes) is:

beatFreq=(70−10)/2=30 cycles/inch.

By looking at FIG. 11, it can be seen that the beat frequency nowresults in a sensitivity of about 2 (compared to 40 for the lowerspacing). The single frequency spikes at 30 for red/green and 50 forluminance, should also be relatively imperceptible as can be seen bylooking up their sensitivities in FIG. 11 (sensitivity of 2 forRed-Green at 30, 20 for luminance at 50).

CONCLUDING REMARKS

Having described and illustrated the principles of the technology withreference to specific implementations, it will be recognized that thetechnology can be implemented in many other, different, forms. Toprovide a comprehensive disclosure without unduly lengthening thespecification, applicant hereby incorporates by reference each of theabove referenced patent documents herein in its entirety. Assignee'sU.S. patent application Ser. No. 12/337,029, filed Dec. 17, 2008, isalso hereby incorporated by reference herein in its entirety.

The methods, processes, components, apparatus and systems describedabove may be implemented in hardware, software or a combination ofhardware and software. For example, the watermark encoding processes andembedders may be implemented in software, firmware, hardware,combinations of software, firmware and hardware, a programmablecomputer, electronic processing circuitry, and/or by executing softwareor instructions with a processor or circuitry. Similarly, watermark datadecoding or decoders may be implemented in software, firmware, hardware,combinations of software, firmware and hardware, a programmablecomputer, electronic processing circuitry, and/or by executing softwareor instructions with a processor or parallel processors.

The methods and processes described above (e.g., watermark embedders anddetectors) also may be implemented in software programs (e.g., writtenin C, C++, Visual Basic, Java, Python, Tcl, Perl, Scheme, Ruby,executable binary files, etc.) stored in memory (e.g., a computerreadable medium, such as an electronic, optical or magnetic storagedevice) and executed by a processor (or electronic processing circuitry,hardware, digital circuit, etc.).

While the above disclosure focuses primarily on image and video signalsour inventive techniques can be similarly applied to audio signals. Forexample, an audio watermark orientation signal is separated intodifferent frequency components and then inserted into left and rightaudio channels. In the case of high fidelity audio (e.g., 3 or morechannels), the audio watermark orientation pattern is separated intothree or more components and embedded in different audio channels.

The particular combinations of elements and features in theabove-detailed embodiments are exemplary only; the interchanging andsubstitution of these teachings with other teachings in this and theincorporated-by-reference patents are also contemplated.

1. A method comprising: obtaining color image data or color video data,the color image data or color video data comprising an encoded signalpattern, the encoded signal pattern aiding detection of an encodedmessage, the encoded signal pattern comprising first frequencycomponents and second frequency components, the color image data orcolor video data comprising first color data and second color data, inwhich the first color data comprises the first frequency componentsencoded therein, and the second color data comprises the secondfrequency components encoded therein; combining the first color data andthe second color data, said combining yielding combined color data;utilizing one or more processors or electronic processing circuitry,detecting the encoded signal pattern from the combined color data, saiddetecting yielding rotation and scale information; and using therotation and scale information to detect the encoded message from thecombined color data.
 2. The method of claim 1 in which the combinedcolor data comprises luminance information, and in which encoded messageis detected from the luminance information.
 3. The method of claim 1 inwhich the first frequency components comprise higher frequencycomponents relative to the second frequency components.
 4. The method ofclaim 3 in which the first color data comprises red-green color data,and the second color data comprises blue-yellow color data.
 5. Themethod of claim 4 in which the combined color data comprises luminanceinformation, and in which encoded message is detected from the luminanceinformation.
 6. A non-transitory computer readable medium comprisinginstructions stored thereon that when executed by one or more processorsperform or control the method of claim
 5. 7. A non-transitory computerreadable medium comprising instructions stored thereon that whenexecuted by one or more processors perform or control the method ofclaim
 1. 8. A method comprising: obtaining color image data or colorvideo data, the color image data or color video data comprising anencoded signal orientation pattern, the encoded signal orientationpattern facilitating detection of an encoded message, the encoded signalorientation pattern comprising first frequency components, secondfrequency components and third frequency components, the color imagedata or color video data comprising first color data, second color dataand third color data, in which the first color data comprises the firstfrequency components encoded therein, the second color data comprisesthe second frequency components encoded therein and the third color datacomprises the third frequency components encoded therein; utilizing oneor more processors or electronic processing circuitry, detecting theencoded signal orientation pattern from the first color data, the secondcolor data and the third color data, said detecting yielding rotationand scale information; and using the rotation and scale information todetect the encoded message from data representing the color image dataor color video data.
 9. The method of claim 8 in which the thirdfrequency components comprise higher frequency components relative tothe second frequency components and to the first frequency components,and the second frequency components comprise higher frequency componentsrelative to the first frequency components.
 10. The method of claim 9 inwhich the second color channel comprises a red-green color channel, andthe first color channel comprises a blue-yellow color channel.
 11. Themethod of claim 8 in which the data representing the color image data orcolor video data comprises luminance information, and the encodedmessage is detected from the luminance information.
 12. A non-transitorycomputer readable medium comprising instructions stored thereon to causean electronic processor to perform the method of claim
 10. 13. Themethod of claim 9 in which the first frequency components are bettersuited to survive compression relative to the second frequencycomponents and the third frequency components.
 15. The method of claim 8further comprising, prior to said act of detecting, combining the firstcolor data, the second color data and the third color data, saidcombining yielding combined color data, in which said act of detectingdetects the encoded signal orientation pattern from the combined colordata.
 16. A non-transitory computer readable medium comprisinginstructions stored thereon to cause an electronic processor to performthe method of claim
 15. 17. A non-transitory computer readable mediumcomprising instruction stored thereon to cause an electronic processorto perform the method of claim
 8. 18. An apparatus comprising: memorystoring color image data or color video data, the color image data orcolor video data comprising an encoded signal pattern, the encodedsignal pattern aiding detection of an encoded message, the encodedsignal pattern comprising first frequency components and secondfrequency components, the color image data or color video datacomprising first color data and second color data, in which the firstcolor data comprises the first frequency components encoded therein, andthe second color data comprises the second frequency components encodedtherein; one or more processors or electronic processing circuitryconfigured for: combining the first color data and the second colordata, said combining yielding combined color data; obtaining rotationand scale information from the encoded signal pattern in the combinedcolor data; decoding the encoded message from the combined color data,in which said decoding utilized the rotation and scale information. 19.The apparatus of claim 18 in which the combined color data comprisesluminance information, and in which encoded message is decoded from theluminance information.
 20. The apparatus of claim 18 in which the firstfrequency components comprise higher frequency components relative tothe second frequency components.
 21. The apparatus of claim 20 in whichthe first color data comprises red-green color data, and the secondcolor data comprises blue-yellow color data.
 22. The apparatus of claim21 in which the combined color data comprises luminance information, andin which encoded message is decoded from the luminance information. 23.An apparatus comprising: memory storing color image data or color videodata, the color image data or color video data comprising an encodedsignal orientation pattern, the encoded signal orientation patternfacilitating detection of an encoded message, the encoded signalorientation pattern comprising first frequency components, secondfrequency components and third frequency components, the color imagedata or color video data comprising first color data, second color dataand third color data, in which the first color data comprises the firstfrequency components encoded therein, the second color data comprisesthe second frequency components encoded therein and the third color datacomprises the third second frequency components encoded therein; and oneor more processors or electronic processing circuitry configured for:determining rotation and scale information associated with the encodedsignal orientation pattern from the first color data, the second colordata and the third color data; and decoding the encoded message fromdata representing the color image data or color video data, in whichsaid decoding utilizes the rotation and scale information.
 24. Theapparatus of claim 23 in which the third frequency components comprisehigher frequency components relative to the second frequency componentsand to the first frequency components, and the second frequencycomponents comprise higher frequency components relative to the firstfrequency components.
 25. The apparatus of claim 24 in which the secondcolor channel comprises a red-green color channel, and the first colorchannel comprises a blue-yellow color channel.
 26. The apparatus ofclaim 23 in which the data representing the color image data or colorvideo data comprises luminance information, and the encoded message isdecoded from the luminance information.
 27. The apparatus of claim 23 inwhich the first frequency components are better suited to survivecompression relative to the second frequency components and the thirdfrequency components.
 28. The apparatus of claim 23 in which said one ormore processors or electronic circuitry are configured for combining thefirst color data, the second color data and the third color data, saidcombining yielding combined color data, in which said decoding decodesthe encoded signal orientation pattern from the combined color data, andin which said combining precedes said decoding.